Steel advice - Cut & weld or Fold?

I would

"Would I be better to make the same V cuts in just the top and bottom 75 mm flanges and try to heat and bend the 150mm dimension with oxy/acetylene heat and just bend the V cuts closed? "

This is how we would do it in the workshop.

I would also score the 150mm section on the inside by a couple of mm's in a straight line because as you heat it you will have a more defined line to bend to.

Once some heat is in it it will bend easily.

Mig welding it would be best but you will need a machine about 200+ real amps to cause penetration.

G/Day Flywest

I would try doing the Mitre Cut and then use the Oxy to bend them, 7mm isn't that thick, and will bend ok, just double check all your measurements as you will only get one go at it.

Cheers

If you have an Oxy - It would look better if you just did a full radius curve. Mark curve top and bottom, cut to shape. Cut off excess from face and heat and wrap around. weld to finish. With the gear you have got - your home and hosed whichever way you decide to go. Cheers Tony

I would bend if I had heat - the way you are going to do it as well.

Flywest Great Idea --But-- Having 7mm steel [mild I presume] is very weighty
Where I live and work has many ferals that try to prevent you to getting home , so my requirements are big/strong bar and good lights
Once I made a bullbar[for 60 series Cruiser] from 6mm mild and it was very heavy , had to get suspension to suit , next made a bullbar[80 series Cruiser] from 4.5mm hi tensile only 60% of the weight , still running strong[ARB do not use heavy steel for same reason] Just remember you have only coils to caary the weight
Lecture finished , It does not matter which method you use as long as the welding is good , if the welding is less than first rate you would be better to just cut top and bottom and bend with act/oxy
Best of Luck
Mick

LOL...

Not feeling so confident now.......after a few hours in the shed..

As for the springs, it has hi lift springs in the rear, so a bit of extra weight to pull them back down somewhere near level would be good - this thing will weigh about 200 kilos with the twin carriers and wheels.

Decided to vut all the way thru and weld after all that - not confident in my ability to bend - as I havent a good engineers vice and bench fixed to concrete to get any leverage on the short ends - and they will be hot being near where the heats been aplied making them hard to grip and apply that leverage.

Dunno what I did, but my math must be screwed up somewhat, - managed to make the cus for one side to take two bends of 45 to get 90 - somehow, I managed to mahe 120 degrees - oops...

Will rectify that next and then tack them @ 90 and do a test fit to the vehicle , to give me some idea where to start the corners for te other side.

I am taking photos - so when I have time will load them to the web and show what I'm up to..

I remember now why I like timber - this steel working is waay to hard!

Damn drop saw won't cut thru 150 mm in depth - so have to cut ahlf way - take the steel out turn it over and reverse the angle on the drop saw and do it form the other side till they meet etc...seem to spend all day chaging the drop saw angles from right to left and back again..

I'll get there - Rome wasn't built in a day.

Cheers & thanks, will report on tomorrows screw ups tomorrow night!